Narrative:

I was working B777-300ER on a south downwind for runway 28L to pair with B757-200 on a straight in to runway 28R. B757-200 was being controlled by another controller. I turned base leg and the other controller advised that he had me in sight and was maintaining visual separation. I was concerned with B777-300ER's ability to speak and comprehend long control instructions and was therefore issuing short control instructions to ensure safety. I verified that B777-300ER had B757-200 in sight and then turned final. At this time; neither aircraft was clearly leading the other; so I verified that B777-300ER had airport in sight. After confirming this; I cleared B777-300ER for a visual approach runway 28L. I then slowed B777-300ER to 160 knots to ensure they would stay behind the B757-200 as planned with the other controller. Around a 13 mile file B777-300ER was only slightly behind B757-200 so I told them 'speed is your discretion to stay behind B757-200.' both aircraft were then shipped to tower frequency. Around a 3 mile file I noticed that B777-300ER was increasing speed; climbing; and passing the B757-200 because tower was sending them around. I later found out that the tower sent the B777-300ER around because of a 'potential overtake.' recommendation; it's hard to say exactly what the 'event' is and what caused it. I'm reporting this because I was advised that this was a deal when in fact it is the same as every other side-by operation we run. The only exception was that I forgot to tell B777-300ER to 'follow' and instead instructed him '...stay behind.' we have been under tremendous pressure from management not to have go-arounds; especially with foreign air carriers flying heavy aircraft. What I believe lead to me forgetting to issue 'follow' was the fact that I was making short control instructions because of the language barrier. Instead of turning and clearing and telling to follow and giving a speed control; I broke one transmission into many and forgot about the 'follow.' I was also working other aircraft and this could have distracted me as well. I have realized that my error is in my phraseology and I will now instruct aircraft 'speed is their discretion to follow preceding traffic' rather than 'stay behind.' since this simple synonym is what prevents an everyday side-by approach from becoming a 'major safety incident' it was paramount that I make this change. It was not indicated to me at what point the preceding aircraft cannot maintain visual separation with the paired aircraft. To my knowledge; if the pilot cannot maintain visual separation; he/she must let ATC know as soon as possible. In this situation; I have not heard whether or not B757-200 ever said they could not maintain visual separation from B777-300ER. This is something that all controllers should see in writing. It would certainly cut down on frequency congestion when obtaining visual separation with multiple aircraft and possibly help establish rules for conducting visual approaches to multiple runways.

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Original NASA ASRS Text

Title: NCT Controller described a go-around event issued by SFO when a B777-300ER for Runway 28L was determined to be overtaking a B757-200 assigned Runway 28R. The reporter's phraseology was not in accordance with directives.

Narrative: I was working B777-300ER on a south downwind for Runway 28L to pair with B757-200 on a straight in to Runway 28R. B757-200 was being controlled by another Controller. I turned base leg and the other Controller advised that he had me in sight and was maintaining visual separation. I was concerned with B777-300ER's ability to speak and comprehend long control instructions and was therefore issuing short control instructions to ensure safety. I verified that B777-300ER had B757-200 in sight and then turned final. At this time; neither aircraft was clearly leading the other; so I verified that B777-300ER had airport in sight. After confirming this; I cleared B777-300ER for a visual approach Runway 28L. I then slowed B777-300ER to 160 knots to ensure they would stay behind the B757-200 as planned with the other Controller. Around a 13 mile file B777-300ER was only slightly behind B757-200 so I told them 'Speed is your discretion to stay behind B757-200.' Both aircraft were then shipped to Tower frequency. Around a 3 mile file I noticed that B777-300ER was increasing speed; climbing; and passing the B757-200 because Tower was sending them around. I later found out that the Tower sent the B777-300ER around because of a 'potential overtake.' Recommendation; it's hard to say exactly what the 'event' is and what caused it. I'm reporting this because I was advised that this was a deal when in fact it is the same as every other side-by operation we run. The only exception was that I forgot to tell B777-300ER to 'follow' and instead instructed him '...stay behind.' We have been under tremendous pressure from management not to have go-arounds; especially with foreign air carriers flying heavy aircraft. What I believe lead to me forgetting to issue 'follow' was the fact that I was making short control instructions because of the language barrier. Instead of turning and clearing and telling to follow and giving a speed control; I broke one transmission into many and forgot about the 'follow.' I was also working other aircraft and this could have distracted me as well. I have realized that my error is in my phraseology and I will now instruct aircraft 'Speed is their discretion to follow preceding traffic' rather than 'stay behind.' Since this simple synonym is what prevents an everyday side-by approach from becoming a 'major safety incident' it was paramount that I make this change. It was not indicated to me at what point the preceding aircraft cannot maintain visual separation with the paired aircraft. To my knowledge; if the pilot cannot maintain visual separation; he/she must let ATC know ASAP. In this situation; I have not heard whether or not B757-200 ever said they could not maintain visual separation from B777-300ER. This is something that all controllers should see in writing. It would certainly cut down on frequency congestion when obtaining visual separation with multiple aircraft and possibly help establish rules for conducting visual approaches to multiple runways.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.